Solid imaging devices have been used for rapid prototyping for models for product development, and, more recently, for manufacturing operations. Solid imaging devices produce three-dimensional objects from fusible powders or photocurable liquids, typically by exposure to radiation in response to computer control. Data representing thin cross-sectional layers of a three-dimensional object provide the computer with control parameters for programs for automated building of the object, typically layer-by-layer. A laser or other source of radiation suitable for solid imaging sequentially irradiates individual thin layers of the build material in response to which the material transforms into a solid, layer-upon-layer, to create a solid imaging product.
Solid imaging is sometimes referred to as “rapid prototyping and manufacturing” and includes such diverse techniques as stereolithography, laser sintering, ink jet printing, and others. Powders, liquids, and other materials for solid imaging sometimes are referred to as “build materials” and the three-dimensional objects that solid imaging produces sometimes are called “builds,” “parts,” and “solid imaging products,” which can include a variety of shapes. The builds are usually prepared on surfaces referred to as “build pads” or “build platforms” that can be raised or lowered to place the surface of a build into contact with imaging radiation. The area where the build material is exposed sometimes is referred to as the “build plane” or “image plane.”
Despite the variety of devices and methods developed for solid imaging, a number of drawbacks have yet to be resolved. The apparatus and methods for practicing solid imaging tend to be somewhat characterized by excessive moving parts and complex systems that can require a good deal of effort to service, maintain, and operate. Laser imaging and UV imaging systems tend to be costly and to place these systems out of reach for many applications. Complex, tedious alignment steps for aligning the radiation source and the image plane reduce efficiency and increase cost. The large vats of liquid resin used in stereolithography are expensive and can become contaminated with pieces of cured resin. Solid imaging devices typically produce “green” three-dimensional products, in which uncured build material wets the surface and causes the product to be tacky and to require cleaning prior to fully curing the product throughout the build.
It would be desirable to provide solid imaging systems and methods that reduce service and maintenance problems and that are simpler to operate, less costly, and more efficient.